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Flo-check valve noise

He have a new boiler installed with indirect water heater. The house has only one zone and the indirect water heater is another zone. There is this Taco 'swet check 241' valve between the heating return and IWH return. My plumber told me that the valve is there to isolate IWH circulation from heating system.

Everything seems to work well except that when the boiler is working for heating( in which case the return water flows through the valve I think), it has gentle knocking noise from the valve. It sounds like some kind of ball bearing hitting the pipe. It's not that loud but when everything's quite in the bedroom I can hear it from the radiator and it gets me. My plumber told me that's the way it is but I have some doubts. Is it really normal to have that kind of noise or a sign of something wrong?

I tried opening up the valve partially and the noise goes away. But then it won't separate the IWH zone from heating zone right?

That's a flow check. It's weighted check valve. It's shouldn't be knocking. If it is....that means it's opening and closing when it shouldn't. That can be caused by alot of different factors.

Normally the big ones are....installed in a vertical position, improper piping....causing pressure differential, and improper application....needing more then one flow check, because of piping and flow.

I suppose the installer had his reasons why he didn't just use IFC pumps or at least circ flanges with IFC style innards.

ifc pumps have there draw backs like cant put on return unless u put purge set up below them (i think that looks horrible) ,put them supply cant manualy open them to drain entire system unless you put a drain ahead of the pump Does not look clean i like traditional piping looks neater, ifc pumps are cheaper than buying a pump and check seperate my 2 cents

Post pics of how it is piped. Something sounds like its piped incorrectly.

Sorry it took me a while to get back with pictures.

The valve is on the heating return before it merges with indirect water heater return at the T show on the picture. It is located close to a 90 elbow- a few inches. Would this be the problem due to turbulance?

I called the Taco tech support and they seemed to believe that the valve is oversized in terms of flow. The weight needs 9gpm of flow rate to float, they say. The funny thing is I measured flow rate of the boiler for the first time because of this and it was 13gpm! I turned down the circulation pump speed to low and it's at 7gpm, which is recommanded for the triangle tube. So based on the fact that it still made noise at 12gpm, it doesn't look like the insufficient flow rate is the problem.

One of my plumber's suggested solution is to keep the valve open a little. It does eliminate the noise but that means IWH return can leak into the heating loop, isn't it?

The valve is on the heating return before it merges with indirect water heater return at the T show on the picture. It is located close to a 90 elbow- a few inches. Would this be the problem due to turbulance?

I called the Taco tech support and they seemed to believe that the valve is oversized in terms of flow. The weight needs 9gpm of flow rate to float, they say. The funny thing is I measured flow rate of the boiler for the first time because of this and it was 13gpm! I turned down the circulation pump speed to low and it's at 7gpm, which is recommanded for the triangle tube. So based on the fact that it still made noise at 12gpm, it doesn't look like the insufficient flow rate is the problem.

One of my plumber's suggested solution is to keep the valve open a little. It does eliminate the noise but that means IWH return can leak into the heating loop, isn't it?

Thanks for the pics.

I don't use swing checks for this reason and others. If I have to use a check, it is the weighted kind. Less hassle.

Not liking the indirect pump orientation. Unless you guarantee there will be 20psi or more at all times in the system.

I don't use swing checks for this reason and others. If I have to use a check, it is the weighted kind. Less hassle.

Not liking the indirect pump orientation. Unless you guarantee there will be 20psi or more at all times in the system.

Low speed on the 15-58 is too low for the Smart.

You have to give me some details on your comments.

1) Taco swet check 241 is a weighted valve, as far as I know. How is swing check different from weighted one?
2) So what do you think is better orientation of the pump? The pressure is about 12-15psi, which is recomanded. 15-58 refers to the pump? The pump is at low setting but I can change it to higher speed. What I don't know is the optimum flow rate for the IWH. At low speed currently, it's more than 15gpm, which seems to me a lot. Shoudl I go higher than that?

Again, I'll have to ask you to elaborate as to what you mean by circulater pulling the valve. The noise only happens when the heat loop is on (valve supposed to be open) not when the water heater loop is on (valve closed).